ISPconfig/ Postfix forward

I have ispconfig installed and there is site: host.maidomain.ee- What I need is all this mail, whitch users are in ispconfig, are comeing to this server to their mailboxes and all mail, whitch users aren't in users table goes to another server(like mailscanner). till today I used for it transport_maps in postfix, but ISPconfig looks for e-mails before it and inf no alias in user table then says no user.

not working - sends all mail to with same name as catch all accout. I need people in other server get their mails to own mailbox.

I think it is quite logic that - postfix checks users tables and if there is no user sends mail to next smtp - or it isn't so easy? this means actually ispconfig doesn't need to confuse situation - postfix just checks users table and sends all unknown to next smtp.